Priority is claimed to Patent Application Number 2001-66748 filed in Republic of Korea on Oct. 29, 2001, herein incorporated by reference.
1. Field of the Invention
The present invention relates to a heat transferring device, and more particularly, to a heat transferring device having an adiabatic unit.
2. Description of the Related Art
As the ongoing development of electronic technology has led to the modularization, miniaturization and increase of the output power of electronic equipment, the amount of heat radiated from electronic equipment per unit area, that is, a ratio of heat radiation per unit area in the electronic equipment, has increased. Accordingly, performance of appropriately processing and controlling heat radiated from such electronic equipment has become an important factor which should be considered during design of electronic equipment.
The temperature of electronic equipment can be controlled using heat conduction, natural convection/radiation of the air, forced convection, cooling by fluid, immersion cooling, or a heat pipe.
In addition, the temperature of electronic equipment can be controlled using capillary pumped loop flow (CPLF) by surface tension which was proposed by Stenger in the NASA Lewis center for the first time. Particularly, since it was proved by Tuckerman and Pease that a micro channel cooling method can be used for cooling high-heat radiation electronic equipment, it is possible to control the entire temperature of electronic equipment by selectively cooling only a member such as a central processing unit (CPU) having a higher ratio of heat radiation per unit area than other members constituting the electronic equipment.
FIG. 1 is a schematic diagram of a heat transferring device using a capillary tube proposed by Stenger. Referring to FIG. 1, a pipe 1 having a passage of a predetermined size through which a working fluid 23 flows forms a loop. An evaporator 2 is provided on the passage of the pipe 1. The evaporator 2 is composed of a case 21 to which heat is transmitted from the outside of the evaporator 2 and a porous body 22 provided within the case 21. The porous body 22 has micro pores inducing a capillary action so that the working fluid 23 can be sucked into the pores due to the capillary action. Then, the working fluid 23 within the pores is evaporated by heat absorbed from the outside. Vapor generated by phase change of the working fluid 23 is discharged through an outlet facing an inlet through the working fluid 23 flows into the evaporator 2 and flows through the pipe 1. As the vapor flows through the pipe 1, the vapor is gradually cooled and finally turned into a liquid. The liquid, that is, the working fluid 23, flows toward the evaporator 2. In such a structure, since vapor is turned into a liquid while it flows through the pipe 1 having a predetermined length, bubbles are formed here and there within the pipe 1.
Such a conventional heat transferring device cannot be manufactured to have a large size and is not suitable to compact electronic devices. In addition, bubbles scattered within a pipe and an uncondensed working fluid between bubbles act as a resistance against the flow of the entire working fluid.
To solve the above-described problems, it is an object of the present invention to provide a heat transferring device in which the flow of a liquid refrigerant can be prevent from being stopped while a compact electronic device is cooled, the flow of a liquid refrigerant can be automatically and quickly restarted when the flow of the liquid refrigerant is stopped for a moment, and the liquid refrigerant can be always supplied to an evaporator, so that the initial operation can be stabilized.
To achieve the above object of the present invention, there is provided a heat transferring device including a lower plate including an evaporator which contacts a heating element and allows a liquid refrigerant to absorb heat transferred from the heating element to thus evaporate, a condenser in which gas flowing from the evaporator is condensed, a gas passage through which the gas flowing from the evaporator into condenser, a liquid refrigerant passage through which the liquid refrigerant flows from the condenser into the evaporator and which includes a portion used as a channel region bordering the evaporator, and an adiabatic unit provided between the liquid refrigerant passage and the gas passage so that elements hindering the flow of the liquid refrigerant can be prevented from being introduced from the gas passage into the liquid refrigerant passage; and an upper plate which contacts some members of the lower plate including the adiabatic unit.
The adiabatic unit includes a first adiabatic unit and a second adiabatic unit which are symmetric or is a single unit parallel to the frame of the lower plate and includes a bended part.
Micro patterns are formed in the condenser, the liquid refrigerant passage, the channel region, and the evaporator such that capillary attraction for the liquid refrigerant gradually increases from the condenser toward the evaporator sequentially through the liquid refrigerant passage and the channel region.
A chamber is provided between the upper plate and the micro patterns formed in the liquid refrigerant passage which does not contact the upper plate by removing the inner side of the upper plate to a predetermined depth.
Regions of the upper plate corresponding to the evaporator, the gas passage, and the condenser are recessed a predetermined depth.
The condenser extends beyond the upper end of the adiabatic unit and borders the liquid refrigerant passage provided between the adiabatic unit and the frame of the lower plate adjacent to and the adiabatic unit.
When the liquid refrigerant passage is divided into two regions by the channel region, the adiabatic unit includes a first adiabatic unit which isolates the gas passage from the first region of the liquid refrigerant passage provided between the condenser and the channel region; and a second adiabatic unit which is formed to be perpendicular to the first adiabatic unit and isolates the evaporator and the gas passage from the remaining second region of the liquid refrigerant passage.
Each of the first and second adiabatic units is a structure including a gap or is a barrier formed of an insulating material, or one of the first and second adiabatic units is a structure including a gap and the other is a barrier formed of an insulating material.
The adiabatic unit is a structure including a gap or a barrier formed of an insulating material.
According to the present invention, a liquid refrigerant is prevented from evaporating while it is flowing from a condenser to an evaporator. The flow of the liquid refrigerant is prevented from being stopped due to bubbles or uncondensed gas. Moreover, the liquid refrigerant spontaneously flows from the condenser through a liquid refrigerant passage into the evaporator. Even if the flow of the liquid refrigerant is stopped for a short moment due to, for example, dry-out, the flow of the liquid refrigerant spontaneously resumes due to the slope of capillary attraction among the condenser, the liquid refrigerant passage, and the evaporator. The slope of capillary attraction allows the liquid refrigerant to flow into the evaporator before the operation of a heat transferring device so that the heat transferring device can operate reliably.